Exposition of Carbone Nanotubes on 3D lung models in the air-liquid interface exposure system to measure oxydative stress and inflammatory response.

Abstract
Carbon nanotubes (CNTs) represent one of the most promising engineered nanomaterials, with
possible applications in advanced engineering and biomedical technologies. During their
production, human exposure to CNTs may occur via inhalation. Therefore, the aim of this study
was to mimic inhalation of multi-walled CNTs (MWCNTs) in vitro as realistically as possible, by
producing MWCNTs aerosols via an Air–Liquid Interface Cell Exposure System (ALICE),
combined with a 3D epithelial airway barrier model cultivated at the air–liquid interface (ALI).
To address the consequences of an extended exposure period, repeated exposures of MWCNTs
(total deposition 1.15 mg/cm2) were applied to the co-culture system, either over one day (one
day repeated exposure) or three days (three day repeated exposure scenario). Although in both
repeated exposure scenarios MWCNTs were found to interact with the different cell types, they
did not induce any cytotoxicity or alterations in cell morphology, nor did they elucidate any
significant increase in pro-inflammatory markers compared to control cultures. Similar results
were also observed following single MWCNTs exposures at deposited concentrations of 0.14,
0.20 and 0.39 mg/cm2. Cells exposed repeatedly to MWCNTs for three days, however did show a
decrease in reduced glutathione levels, although not significant (p40.05). In conclusion, we
have presented a realistic in vitro alternative to mimic occupational exposure of MWCNTs and
by applying this approach it was shown that repeated MWCNT exposures to lung cell cultures
at the ALI elicit a limited biological impact over a three day period.